We designed the study to compare the oncologic and renal function outcomes of off-clamp, laparoscopic partial nephrectomy (OCLPN) and conventional laparoscopic partial nephrectomy (HCLPN) for renal tumors.

Between March 2008 and July 2015, 114 patients who underwent laparoscopic partial nephrectomy (LPN) of a renal neoplasm were studied. We performed LPN without hilar clamp on 40 patients (OCLPN, Group 1), and conventional LPN with hilar control and renorrhaphy on another 40 patients (HCLPN, Group 2). We retrospectively reviewed the medical records of each patient's age, sex, R.E.N.A.L. nephrometry score (RNS), operation time, complications, hospitalization period, tumor size, positive resection margin, histologic classification of tumor, pathologic stage, Fuhrman grade, estimated blood loss (EBL), warm ischemic time (WIT), and estimated glomerular filtration rate (eGFR) before and one year after surgery.

There were no significant differences in age, sex, preoperative eGFR, EBL, surgical (anesthesia) time, and tumor size between the two groups. The mean eGFR was not significantly different between the OCLPN and HCLPN groups 1 month (95 and 86.2 mL/min/1.73 m², respectively; P = 0.106), 6 months (92.9 and 83.6 mL/min/1.73 m², respectively; P = 0.151) and 12 months (93.8 and 84.7 mL/min/1.73 m², respectively; P = 0.077) postoperatively. The change in eGFR after one year was 3.9% in the OCLPN group and −7.9% in the HCLPN group.

OCLPN was superior to HCLPN in preserving renal function one year after surgery, and there was no statistically significant difference in tumor treatment results.